Computer-enabled communication systems incorporate an ever-increasing number of features. Accordingly, the number and types of messages that must be communicated between network elements, such as clients and servers, increase. Messages include for instance network element status information, synchronization information, network element capabilities, identification information, authorization information, instant messages, real-time communication messages such as audio and video packages, etc.
The main body of data exchanged in a communication system consists of the content information as such. In a real-time audio/video communication session, the content information consists of audio/video packages that are formed when sound and images are captured and translated into a digital format. Along with the content information as such, control messages such as information regarding a user's identity or network presence, are exchanged. The content information and control messages may be more or less integrated.
Typically, when a first user of a communication system wishes to send a message to a second user, the first user sends his message to a message server that the second user will query in order to see if there are new messages for him. In an email system, for instance, a sender forms an email to be delivered to a recipient. Subsequently, the email is transmitted to an email server along with information identifying the recipient. Users of the email system will send frequent query messages, a type of control message, to the email server in order to determine whether they are recipients of new emails. When the recipient queries the email server after the sender's email has been delivered to it, he will receive an indication that he is a recipient of the email. To have a sense of real-time delivery, users may prefer to query the email server quite frequently, for instance once every second or even more frequently. Upon receiving the indication that he is a recipient of the message, he may request and receive the message from the email server.
A query may contain authorization information, such as a user identity and a password, possibly along with an authorization certificate of some kind. The query may also include a time stamp or other unique signature. If the email system is used by many users, the resources required to handle the queries may eventually exceed the system's capacity. For instance, the email server's central processing unit (CPU) may be unable to process all the data going in and out. Exchange of emails and queries to and from the email server may also require network resources beyond the system's capacity
The result is that the email server stops functioning correctly, which in turn means system downtime and frustration for the system's users who depend on the email system to deliver their messages.